Variations of 222Rn Content in Above- and Underground Conditions

Abstract—The article presents the results of measuring 222Rn activity and its daughter decay products in the air of underground laboratories of Baksan Neutrino Observatory, Institute for Nuclear Research, Russian Academy of Sciences (BNO INR RAS) at different distances from the entrance. The measurements were carried out with a cylindrical air pulse ionization chamber. It has been shown that the radon content in the flow of ventilated air, within the measurement accuracy, does not depend on the length of the path traveled, but increases abruptly in the locations of sources of underground gas and water emissions. Various mechanisms of air enrichment with radon are considered. The research methodology is presented, and the results of measurements of radon emission from the rocky soil of the walls of an underground room are presented. The results of measuring the radon content in water from various above- and underground sources using a low-background gamma spectrometer based on a semiconductor detector (SCD) made of ultrapure germanium are presented.